As technology advancements continue to miniaturize electronic circuits, portable electronic devices are quickly becoming capable of more and more computationally powerful operations. Many complex program applications, once only executed on large desktop computers, can now be found running on modern “wearable” computer devices. For instance, modern personal digital assistants (PDAs), cellular phones, and smart watches may include a text and e-mail editor, a database program, and an Internet browser.
One complicating factor in executing complex programs on such small computer devices is the lack of physical space available for a practical user interface compatible with complex program applications. Wearable computers often have a small amount of surface area on which to provide a display screen and user input hardware. Because of this spatial constraint, small electronic devices tend to miniaturize input hardware, such as push buttons, knobs, and joysticks, so that less surface area is taken up by input elements. Miniaturizing input hardware, however, often reduces their handiness and makes portable computing devices awkward and difficult to use.